This invention relates to rotary vibration dampers.
It is known to provide a rotary vibration damper comprising one or more vanes secured to a rotor and mounted for rotational oscillatory movement within and relative to a housing, the housing having an arcuate wall and other walls co-operable with said vane or vanes to define chambers which are filled with damper fluid and whose volumes are complementary, their relative volumes being variable in dependence on the position of the vane or vanes, the complementary chambers being interconnected by one or more restricted fluid flow paths through which vibration-damper fluid can flow at a restricted rate, and a flow control member movable to vary the flow area of said one or more flow paths.
An object of the present invention is to provide, in such a vibration damper, a simple arrangement for varying the flow area of the restricted flow path or paths.